1. Field of the Invention
The present invention relates to composite substrates, production methods thereof, and acoustic wave devices.
2. Description of the Related Art
The use of an ultrathin piezoelectric layer is expected to realize an acoustic wave device which may be operated at a higher frequency than heretofore possible. Chemical vapor deposition (CVD) and the Smart Cut technology are two exemplary methods capable of forming such thin layers. These two methods are known techniques. For example, the Smart Cut technology is described in Patent Literature 1.